Copter: Helicopters to use motor interlock logic.

Also, remove motor interlock pre-arm check to streamline logic.

ArduCopter/heli.cpp

@@ -16,7 +16,8 @@ static int8_t heli_dynamic_flight_counter;
 // heli_init - perform any special initialisation required for the tradheli
 void Copter::heli_init()
 {
-    // Nothing in here for now.  To-Do: Eliminate this function completely?
+    // helicopters are always using motor interlock
+    set_using_interlock(true);
 }
 
 // get_pilot_desired_collective - converts pilot input (from 0 ~ 1000) to a value that can be fed into the channel_throttle->servo_out function
@@ -142,24 +143,30 @@ void Copter::heli_update_rotor_speed_targets()
 
     if (motors.armed()) {
         switch (rsc_control_mode) {
-            case AP_MOTORS_HELI_RSC_MODE_NONE:
-                // even though pilot passes rotors speed directly to rotor ESC via receiver, motor lib needs to know if
-                // rotor is spinning in case we are using direct drive tailrotor which must be spun up at same time
             case AP_MOTORS_HELI_RSC_MODE_CH8_PASSTHROUGH:
-                // pass through pilot desired rotor speed
-                motors.set_desired_rotor_speed(rsc_control_deglitched);
+                // pass through pilot desired rotor speed if control input is higher than 10, creating a deadband at the bottom
+                if (rsc_control_deglitched > 10) {
+                    motors.set_interlock(true);
+                    motors.set_desired_rotor_speed(rsc_control_deglitched);
+                } else {
+                    motors.set_interlock(false);
+                    motors.set_desired_rotor_speed(0);
+                }
                 break;
             case AP_MOTORS_HELI_RSC_MODE_SETPOINT:
                 // pass setpoint through as desired rotor speed
                 if (rsc_control_deglitched > 0) {
+                    motors.set_interlock(true);
                     motors.set_desired_rotor_speed(motors.get_rsc_setpoint());
                 }else{
+                    motors.set_interlock(false);
                     motors.set_desired_rotor_speed(0);
                 }
                 break;
         }
     } else {
         // if disarmed, force desired_rotor_speed to Zero
+        motors.set_interlock(false);
         motors.set_desired_rotor_speed(0);
     }
 

ArduCopter/motors.cpp

@@ -85,9 +85,11 @@ void Copter::auto_disarm_check()
     // always allow auto disarm if using interlock switch or motors are Emergency Stopped
     if ((ap.using_interlock && !motors.get_interlock()) || ap.motor_emergency_stop) {
         auto_disarming_counter++;
+#if FRAME_CONFIG != HELI_FRAME
         // use a shorter delay if using throttle interlock switch or Emergency Stop, because it is less
         // obvious the copter is armed as the motors will not be spinning
         disarm_delay /= 2;
+#endif
     } else {
         bool sprung_throttle_stick = (g.throttle_behavior & THR_BEHAVE_FEEDBACK_FROM_MID_STICK) != 0;
         bool thr_low;
@@ -184,8 +186,13 @@ bool Copter::init_arm_motors(bool arming_from_gcs)
         did_ground_start = true;
     }
 
+#if FRAME_CONFIG == HELI_FRAME
+    // helicopters are always using motor interlock
+    set_using_interlock(true);
+#else
     // check if we are using motor interlock control on an aux switch
     set_using_interlock(check_if_auxsw_mode_used(AUXSW_MOTOR_INTERLOCK));
+#endif
 
     // if we are using motor interlock switch and it's enabled, fail to arm
     if (ap.using_interlock && motors.get_interlock()){
@@ -739,13 +746,12 @@ bool Copter::arm_checks(bool display_failure, bool arming_from_gcs)
         return false;
     }
 
-    // always check if rotor is spinning on heli
-#if FRAME_CONFIG == HELI_FRAME
     // heli specific arming check
-    if ((rsc_control_deglitched > 0) || !motors.allow_arming()){
+#if FRAME_CONFIG == HELI_FRAME
+    // check if rotor is spinning on heli because this could disrupt gyro calibration
+    if (!motors.allow_arming()){
         if (display_failure) {
-            gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("Arm: Rotor Control Engaged"));
-        }
+            gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("Arm: Rotor is Spinning"));        }
         return false;
     }
 #endif  // HELI_FRAME